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By Donald W. Breck

Zeolites were first recognized as a new group of minerals by Cronstedt with the discovery of stilbite in 1756. The word zeolite was coined from the two Greek words meaning "to boil" and "a stone" because of the loss of water when heated in the mineralogist's blow pipe. (1) In 1845 it was discovered that certain soils have the power of retaining ammonium Salts. (2) These were the first ion exchange experiments. Later it was discovered that it was the hydrated silicates in the soil that produced this phenomenon and several years later a paper was published dealing with the action of dilute salt solutions on silicates which showed that this base exchange principal, which we now call cation exchange, is reversible. The quantitative cation exchange behavior of zeolite minerals, such as chabazite, was studied. As a result any aluminosilicate which exhibited the property of ion exchange was referred to as a "zeolite;" even today the term has been applied to clay minerals as well as synthetic organic ion exchange resins.

Jan 1, 1973

By Earle Bagley

In late 1971, the Sun Company, then known as Sun Oil Company, acquired a large surface mineable federal coal lease with the thought that those coal measures within its boundaries would provide a future feedstock of either coal or coal liquification. Our Cordero lease was one of the last Federal coal leases let before the recent decade long leasing moratorium. Because of the tremendous demand for compliance steam coal for the electric power industry, a decision was made to develop the property to serve that market. In 1974, Sunoco Energy Development Company (SUNEDCO), the non- oil and gas energy unit of the Sun Company, began engineering studies for development of the lease. The mine was originally designed at a 12.0 million ton per year capacity. The Cordero Mining Company was formed to mine and operate the property. Construction of the facilities adjacent to the lease began in January 1975. Due to the Sierra Club versus Department of Interior Secretary L. B. Morton suit, work within the lease was delayed until mid-1976 when pre-stripping of the overburden began.

Jan 1, 1982

By Donald G. Wieland, James H. Meinholz

INTRODUCTION The Milwaukee, Wisconsin Metropolitan Area provides an ideal opportunity to review the advancement of the art and science of mixed face tunneling in the past 65 years. Although there were earlier tunnel projects in the Milwaukee area, by other agencies, the majority of those driven in the Twentieth Century have been done under contract with the Milwaukee Metropolitan Sewerage District through the agency of the Sewerage Commission of the City of Milwaukee and the Metropolitan Sewerage Commission of the County of Milwaukee. Legal Description of District The Milwaukee Metropolitan Sewerage District was created by the Wisconsin Legislature in 1921 together with the Metropolitan Sewerage Commission of the County of Milwaukee. This concept of subregional wastewater control was an outgrowth of an investigation and report from a commission appointed by the Common Council of the City of Milwaukee in 1909 to study final sewage disposal for the City. In 1911 that Commission, comprised of J. W. Alvord, George C. Whipple and Harrison P. Eddy, recommended that the City construct a water filtration plant, construct a Menomonee River flushing works, expand the intercepting sewer system and, after a thorough study of the then existing and developing methods of sewage treatment, construct a sewage treatment plant. In response to those recommendations, the Wisconsin Legislature, in Chapter 608 of the Laws of 1913, created the Sewerage Commission of the City of Milwaukee. Recognizing that the improvement of surface water quality would require action on a watershed basis, the Legislature, in Chapters 554 and 590. of the Laws of 1921, created the

Jan 1, 1979

By Tom Ireland, Tony Rock

The proposed 1.83km long twin bore A3 Hindhead road tunnel planned for contruction in 2008 is being delivered under a Highways Agency Early Contractor Involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunneling medium is a ‘soft rock’ sandstone for which there was little previous tunneling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240m long portal section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels, and the innovation included in the ‘permanent’ primary lining design.

Jan 1, 2007

By H. S. Ten Eyck

The major underlying threat to man's successful survival and happy existence on this planet is our own prolification. This poses an even greater threat to the future of civilization than continued wars and even "The Bomb" itself. Just the predictions of the world's population trend are awesome and demand our serious thought. This trend has been given the now well-known term, "The Population Explosion" - and this is literally what is taking place throughout most of the countries around the globe. Today, the world's resources support approximately 3.3 billion people. Based on the present world population growth rate of 2.1 percent, there will be another 65, million just one year from today. Such an increase in one year means that the world will add a greater population than that of Mexico and Canada combined. Projecting at this remarkable, but unchecked, growth rate, 6.7 billion people will be competing for survival by the end of this century.

Jan 1, 1966

By O. Ofor

Coal fines of less than 0.5 mm particle size, discarded as too fine for gravity separation, were subjected to flotation tests at varying pH and temperatures using modified dosages of kerosene as oil phase and methylisobutylketone (MIBK) as frother. Optimal coal recovery of over 74% was obtained using 200 kg kerosene and 4 kg MIBK per ton of coal fines at a pH of 9.7 and an ambient temperature of 26° C. The coal concentrate obtained under these optimal recovery conditions assayed 9.10% ash, 0.35% sulfur and 0.011% phosphorus, representing reductions in the ash, sulfur and phosphorus contents of approximately 75%, 43% and 8.3%, respectively. Its gross calorific value was 32.9 MJ/kg, its percentage of volatile matter measured 30.6 and the fixed carbon content was 66.3% (d.a.f). Caking tests showed the optimal concentrate has a standard welling number of 1 and is a Gray-King coke type C. These results show that the optimal flotation product could be utilized for such industrial purposes as steam raising or for processing in gasworks, but it would be unsuitable for metallurgical coke production.

Jan 1, 1993

By C. Pace, D. Darlington, A. Montera, C. Lingren

"A phosphate beneficiation plant in Utah is using isotope-based Prompt Gamma Neutron Activation Analysis (PGNAA) technology to analyze the entire slurry streams of the incoming feed and final product in order to adjust the flotation circuits in near real time and optimize the plant output. The plant has gained greatly improved visibility/control and has reduced product variability for improved profitability and product quality. This paper takes a look at the economics as well as application details and the difference this technology provides in a phosphate application. SIMPLOT PHOSPHATES INTRODUCTION Simplot’s Vernal, Utah Phosphate Mine and Mill are located in the northeast corner of the state in the Uinta Mountains along US Highway 191, eleven miles north of the town of Vernal. The phosphoric acid and fertilizer plant fed by the Vernal mine is located 94 miles Northeast of Simplot Phosphates in Rock Springs, WY.At the Vernal plant, loader and shovel mining to 85 Ton capacity trucks is done at an annual rate of 3.8 Million tons of ore. Run of mine ore is crushed in a mineral sizer to minus 14 inch diameter at the rate 11,500 tons a day and transported to the SAG Mill’s 130,000 ton surge stockpile by overland belt. ORE RESERVES The ore is a Phosphoria Formation of sedimentary rock type dating to the Permian Age. The ore body rests over a 25 mile area on Weber Sandstone from the Pennsylvania and Permian geologic period. Layers of Phosphate Rock can vary in thickness from 0.3 up to 2.1 feet, alternating with layers of Mudstone. The eastern edge of the ore’s body Panel “G” runs 16 feet deep with a feed grade of 21.5% P205 with lower MgO diluents of less than 2.79%."

Jan 1, 2016

By RENE GOMEZ, RAUL CASTRO

Estimation tools and models are now available to estimate fragmentation, but some variables have yet to be studied to understand their effect on the fragmentation process. One such variable whose mechanisms have yet to be studied is the residence time, which in block caving directly depends on the distance that fragments travel from their original position in the broken ore to the drawpoint. In this study, granular material fragmentation was characterized during its flow to understand its characteristics and mechanisms. The results show that the breakage of fragment singularities occurred mainly within medium and smaller sizes, increasing fine material during flow. Thus, the main fragmentation mechanism in experiments was identified as abrasion between rock fragments where fine material continuously increases as distance increases in spite of the high rock strength and the piston flow movement used. The results presented here can be applied to incorporate fragmentation during flow of large travel distance of ore such as in block caving.

Those involved in the mining and minerals industry really are an optimistic bunch. Faced with an economic downturn that has spread across the globe ? one, some say, that crept up on everyone ? mining professionals remain hopeful that the industry will return. An example of that optimism is the attendance at two of the industry?s key conferences and exhibitions. In February, more than 4,200 people attended the SME Annual Meeting and Exhibit in Denver, CO. And a week later, in Toronto, Ontario, more than 18,000 were on hand for the Prospectors and Developers Association of Canada?s (PDAC) meeting. Both are respectable numbers and run contrary to meeting attendance figures during previous downturns when attendance and the numbers of exhibitors fell off significantly. Like other downturns, this most recent one has resulted in massive layoffs, curtailments of production and outright closures. Exploration has been hard hit and many junior mining and exploration companies will either disappear or be swallowed up by others. Gold is its usual self The PDAC generally attracts the gold mining and exploration sectors. So that might explain some of the optimism at the meeting. Unlike base metals and construction materials, gold, not surprisingly, is doing well. And most of the companies in the Investors Exchange at PDAC were involved with gold. While the balance sheets for most base metals companies look bad, gold companies appear to be not as hard hit. Gold is doing what it usually does during a downturn ? act as a safe haven while the value of other assets collapse worldwide. Governments around the world are preparing to pour trillions of dollars in an attempt to resuscitate their economies. This will likely lead to inflation, some experts at the PDAC convention said, which will be good for gold. And gold mining companies are also benefiting from lower production costs. The result is that some gold watchers believe gold could reach $64/g ($2,000/oz) at some point.

Jan 1, 2009

By J. K. Shurie

Calcined high quality bauxite is a staple raw material of the abrasive industry world-wide. The author discusses the factors which affect the economic value of calcined abrasive grade bauxite, and proposes an approach to the problem of estimating the relative value of available materials.

Jan 1, 1990

global mining boom and in-creased demand for iron ore has lead to a resurgence in the mining industry in Minnesota. At the combined 81st Annual Minnesota Section of SME Meeting and 69th Annual University of Minnesota Mining Symposium, April 15-16 in Duluth, MN, this resurgence was the hot topic as new mining projects were featured in the keynote session. The meeting attracted more than 400 mining industry professionals, including engineers, executives, mining managers and suppliers from around the world. This year?s theme was ?New Ventures in Mining.? The meeting included concurrent technical papers sessions, a keynote session that featured three distinguished speakers and a panel discussion that provided updates on new mining developments in the state. The Minnesota Section of SME technical papers were presented in concurrent sessions, one on mining and one on mineral processing. The mining session included papers on drilling, ore blending, slope stabilization, dust control and operations management. The mineral processing session included papers on plant-control technology, ball mills, pellet strength and fans. Also offered was an SME short course titled ?Simulation based pellet induration optimization.? The Minnesota Section of SME held its annual business meeting during the conference. The 69th Annual University of Minnesota Mining Symposium technical sessions were held on April 15 and also consisted of concurrent sessions on mining and mineral processing. Mining session topics included logistics management, real-time performance measurement, uses for taconite aggregate and environmental issues. The mineral processing session included papers on ore liberation characteristics, zeta potential studies, induration modeling, fuel optimization and conveyor belts. The combined conference included a tradeshow with more than 80 booth spaces featuring vendors offering products and services to Minnesota?s booming mining industry. More than 900 people, including conference registrants and special invited guests of the vendors, at-tended the tradeshow opening reception. This was the largest trade show in many years ? an indication of the vitality of the mining industry in Minnesota.

Jan 1, 2008

By J. Gathje

Normal process development for pressure-preoxidation treatment of refractory gold ores starts with laboratory batch autoclave tests. That is followed by continuous autoclave pilot-plant testing to confirm the process options. This scheme will generally provide good information showing the effects of grind size, time and temperature. And it will indicate whether autoclave preoxidation will produce solids that are amenable to cyanidation for gold recovery. However, several test programs have shown that the cyanide-leaching responses of treated solids from the batch tests can differ considerably from those achieved by the continuous pilot-plant autoclave. It has become apparent that laboratory investigations should extended to include the use of a semicontinuous autoclave test procedure. Santa Fe Pacific Gold conducted several months of metallurgical investigations for a major refractory sulfide gold deposit. The project started with batch tests to investigate and optimize the primary variables, such as grind size, retention time and temperature. These tests were conducted using a representative whole ore composite.

Jan 1, 1995

By John A. Bischoff, Francis S. Kendorski

A technique that has been used for inspection and appraisal of rock tunnels is described. It enables a rapid and complete record to be made of those factors necessary for the engineering assessment of the rock conditions surrounding a tunnel. Full understanding of the regional geology, and a careful recording of data concerning the principal geological and construction factors is essential basic data for a tunneling project, whether the tunnel is under construction or is already in service. A methodical recording of data concerning general geology, shears, fracture orientations, spacing, persistence, rock classification, water condition, shear frequency, excavation method, blasting procedure, and rock stabilization and support methods, combined with a photographic record, can be completed by experienced engineers and geologists at the rate of over 1000 feet of tunnel per shift.

Jan 1, 1976

By Drupad B. Desai

Baltimore Region Rapid Transit System project final design began in 1973. The Section A of the planned Phase I is scheduled to go into revenue service in late 1982. The subway line structures include earth tunnels, rock tunnels and cut-and-cover structures. Final designs were performed by both the DMJM/KE staff and by outside subconsultants. This paper deals with Section A of the program. (Fig. 1.) The overall program cost for Section A is estimated to be $721 million. The cost for construction and owner furnished equipment is estimated to be $600 million, including contingency and escalation to time of construction. The remaining amounts are for right-of-way, design, construction management and agency (MTA) costs. The Section A line structures, including station lengths, are divided as shown in Table 1. [ ]

Jan 1, 1979

By Vasilis Androulakis, Caroline Gerwig, Zach Agioutantis

Mining operations that involve caving of the overlying strata are designed so that caving occurs in a controlled manner by progressive overburden failure. However, there are many cases where the overlying strata bridge over the caved area for longer periods than anticipated and desired. As the caved area expands with the advance of the mining panel, excessive amounts of energy accumulate in the roof strata which will be rapidly released when the overburden eventually fails.

By J. Platt

Debate over acid rain legislation has presented a moving target for coal and utility company planners attempting to figure out how legislation will affect their business environment. In spite of disagreement among experts, the prospect for continued change, and persistent --perhaps even growing --uncertainty, a great deal has been learned about coal market dynamics. This paper reviews progress and describes some of the major problems and controversies.

Jan 1, 1990

By T. R. Jr. McMillan

Introduction Examining the short- and long-term job prospects for engineers in the coal industry might include looking at coal tonnage projections, future export markets, federal regulations, and the decrease in overall graduates. But coal is the US most competitive basic industry. As such, why not go back to basics? That is, there are three basic challenges that need to be faced by students, faculty, and members of the coal industry. These challenges are counseling, career placement, and professionalism. Counseling Counseling can include elementary, high school, and college students, as well as individuals already employed. But what happens to students after they have selected a course of study at a particular university? As shown in Fig. 1, only 87,000, or 7.25% of our graduates have technical degrees. Generally, there is a strong market projected for these engineering graduates. However, many students who have majored in other nontechnical curriculums, have to scramble for jobs. This says something about our ability to make students aware of where the real job opportunities are. As a student spends four or five years pursuing a degree, he or she is looking for professional guidance. The student has the right to expect "real world" counseling - counseling that is not "the way it should be" but "the way it is." The influence of faculty members is significant. They should take this long opportunity to tell students not what they want to hear or what the problem's of academia or the industry are, but what the real job market is all about. If faculty do not use this opportunity, they in-advertently-through omission - mislead their students. Once a student graduates and is a working alumnus, faculty should take advantage of their relationship with the student and continue to stimulate conversation leading to a two-way exchange of ideas and information. Faculty should also encourage and solicit financial support for their mining departments from their alumni. These monies, in many cases, will be matched dollar for dollar or more, depending on the company the alumnus works for. In the private sector, the responsibility is to communicate with faculty and students. Alumni can be effective by participating in this two-way dialogue with their professors at meetings, technical seminars, and conventions. In many cases, alumni will employ summer or co-op students in their organizations. While getting to know these students, industry members should level with them on where the true opportunities are and what it takes to be successful. It is important to communicate with both faculty and students candidly on both the posi-

Jan 2, 1985

By R. A. Williams

Surface and electrochemical techniques have been used to describe the surface chemistry of ferrosilicon powders, as a function of pH and electrochemical potential, for conditions typical of operating DHS plants. The practical consequences on the likely corrosion behaviour and associated electro- kinetic particle-particle interactions (which affect stability to sedimentation) in the suspension, are discussed.

Jan 1, 1987

By C. Ford, R. E. Salas Rojas, J. P. Contreras Rodriquez, S. A. Pierce

Heightened environmental consciousness has resulted in the development of various international accords dealing with natural resource management. This international awareness is now being translated into regional and local initiatives that proactively implement collaborative environmental management programs. One such program was recently initiated in northern Chile in recognition of the interconnection of Andean salars. Cooperative efforts between industry, governmental agencies and academic professionals have resulted in the implementation of simultaneous environmental monitoring of flora and fauna in the salars of northern Chile. This coordinated effort is leading to an improved understanding of the migratory patterns of South American fauna, as well as improved access to an expanded database for the multiple user groups associated with the Andean salars. The El Abra Mine is actively participating in these coordinated monitoring efforts.

Jan 1, 1999

By Yi Yang, Xiuzhu Su, Wei Sung Ng, Shuiping Zhong, Miao Chen

With over 260 tons of gold reserves, the Shuiyindong gold mine is one of the largest Carlin-type gold deposits in China. A particular challenge in the processing of the ore is the presence of carbonaceous compounds, which can cause substantial losses in recoveries via the preg-robbing and adsorption of gold. To investigate the structural properties of the native carbon and to compare between different characterization techniques for such compounds, pre- and post-flotation mineral samples containing 0.9–4.8% non-carbonate carbon from the Shuiyindong mine have been examined via mineralogical and thermogravimetric approaches, as well as spectroscopic techniques, including X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine edge structure spectroscopy (NEXAFS), solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, Raman spectroscopy and preg-robbing measurements. NEXAFS and DRIFT yielded the most reliable results, indicating that 60–75% of the organic carbon in all samples consist of aliphatic alkenes with substantial unsaturated content, highly similar to activated carbon, with the remainder being graphitic and humic. Speciation by XPS was sub-optimal due to spectral overlaps between graphitic and aliphatic carbon, and between carboxylic and carbonate functionalities, while NMR spectroscopy could not provide reliable speciation of the carbon groups. The preg-robbing strength was strongly correlated to the aliphatic content and structural disorder in the carbon, while no such relationship was found with the graphitic and humic content.

Nov 29, 2021